Air-water syringes have been used by dentists and qualified dental technicians in conjunction with a wide variety of dental procedures such as, for example, the routine cleaning of teeth and filling cavities.
Typically, these known air-water syringes include a body portion that is generally shaped so that it can be easily held by the dentist or dental technician during use, and a nozzle or tip that extends away from the body portion. Usually two passageways are provided, both of which extend through the body portion and the nozzle so that pressurized air and water can be introduced into such passageways, respectively, and emitted from the extending end of the nozzle portion at a predetermined flow rate. A separate control button for each of the two passageways is mounted in the body portion of the syringe so that the user can, by pressing such control button, operate a control valve in each passageway to thereby control the flow of the water and the air which is emitted from the nozzle.
In typical usage, the dentist or dental technician grasps the handle portion of the syringe, inserts the nozzle portion into the open mouth or oral cavity of the patient, and then manipulates the syringe while simultaneously operating the air or water control buttons so that jets of air and/or water (or a mist formed by depressing both buttons) can be directed, as desired, at any selected tooth or gum portions within the oral cavity for any number of purposes, such as using the water jet for flushing away blood and/or particulate matter, or using the air jet for drying a desired area within the oral cavity.
To accomplish its various functions, such as the aforesaid flushing and drying functions, the air and water must be emitted from the nozzle at a relatively high rate of flow, and, as a result, the jet of air or water tends to cause particles of water, blood, contaminants, and the like to be splashed or propagated outside of the oral cavity and in the immediate vicinity which is occupied by the dentist or dental assistant who is using the syringe. The exposure to this splashback of elements, such as blood and contaminants, creates significant health hazards for the dentist or dental technician who must have their hands and faces close to the patient's oral cavity while performing normal dental procedures, and this health hazard has increased exponentially with the increase in AIDS since the AIDS virus can be transmitted directly to the dentist or dental technician by the splashback from the mouth of an AIDS victim.
One known device for dealing with the aforesaid splashback problem is a face shield or mask that includes a translucent shield positioned over the dentist's face to act as a barrier to any splashback. While these masks do provide some protection against splashback, they have a number of disadvantages, such as being cumbersome to wear, particularly when more difficult and delicate dental procedures are being performed. Also, this shield must be cleaned at frequent intervals, and perhaps most importantly, the shield protects only the face of the user, and it provides no protection for other parts of the body (such as the arms of the user) or for surrounding surface areas where the presence of contaminates may cause additional cross-contamination to occur.
An effort had been made to deal with the aforesaid problem of splashback by providing an air barrier around the mouth of a dental patient on whom dental procedures are being performed, as disclosed in Paschal U.S. Pat. No. 4,967,320 issue Oct. 30, 1990. While this air barrier system is very effective, it requires special equipment and in a few instances, the splashback may have sufficient velocity to penetrate the air barrier. In any event, there does not appear to be any known arrangement, prior to the present invention, that can be associated directly with an air-water syringe to protect the user of such instruments from harmful splashback.